On 06/07/2010 09:32 AM, Brett Slatkin wrote:
Generally I agree with this approach. The needs of a self-describing document/payload are different than those of a document/payload that requires the headers for correct interpretation. The same applies to HTML and hAtom, where the hub link would be in the html<head> and the headers are mostly irrelevant. This also has an effect on security, where the generic HTTP version must preserve the fidelity of the payload's headers, whereas the self-describing document can drop them.
To be fully general, the notification payload could be an HTTP response encapsulated in an HTTP request. That way the subscriber will get all of the HTTP headers exactly as returned by the topic URL, and most importantly the subscriber will get the HTTP status code which will allow the subscriber to detect, for example, a 410 Gone response indicating that the resource has been permanently removed.
The challenge with this approach, of course, is that some HTTP frameworks may not provide a convenient way to parse an arbitrary payload as an HTTP request, and it complicates the common case of just getting notifications of changes to the content.
